Will coronavirus restrictions lead to more advanced cancers?

My pathology lab once faced a daily flood of colon polyps, pap smears, and prostate biopsies. Suddenly, our work has dried up. The coronavirus pandemic has cleared out operating rooms and clinics across the country. Endoscopy and radiology suites have gone dark.

Pathology is largely driven by mass screening programs, and the machinery of screening has grinded to a halt during the COVID-19 pandemic. The American Cancer Society currently recommends that “no one should go to a health care facility for routine cancer screening at this time.”

But malignancies are still growing and spreading even though a great deal of medical care is on hold. The most urgent cancer care is still taking place; the risks of delaying treatment for patients with advanced or symptomatic cancer are obvious—these tumors can cause severe pain and life-threatening complications.

But that leaves us with a more complex and uncomfortable question: Will the pause in screening ultimately leave patients with tiny, asymptomatic cancers or precursor lesions worse off? What will a delay mean for those with ductal carcinoma in situ or small breast cancers? What’s the long-term effect of all those dysplastic nevi and early melanoma left unexcised by dermatologists? Perhaps more troubling, what about the spreading kidney cancer that may have turned up as an incidental finding on a CT scan?

COVID-19: A natural experiment

For many years, we’ve been dealing with the other side of the screening question: overdiagnosing and treating cancers that would probably never harm the patient. Overdiagnosis has been on a decades-long rise due to organized screening like PSA testing and mammography, as well as through ad hoc detection from heavier use of medical imaging. All of these have been disrupted by the pandemic.

Because the correlation between medical interventions and cancer overdiagnosis is clear, we can safely assume that overdiagnosis will decline during the pandemic. But what will be the net effect? Early detection of cancer undoubtedly saves some lives, but how many and at what cost has been a seemingly intractable debate.

Until now.

The coronavirus outbreak will be a natural experiment like no other. Economists and epidemiologists love to study “natural experiments” – systemic shocks that shed light on a complex phenomenon.

The unexpected nationwide delay in screening will undoubtedly inform the debate on overdiagnosis. For one, we can learn whether less intensive screening leads to more advanced cancers. Because screening will probably return to normal at different times across the country, we can almost simulate a randomized trial. Will this transformative data be a silver lining to this awful time?

The pressure to ‘fight’

The pandemic has also raised a question about cancer screening that goes beyond data: Why has the loud epidemic of coronavirus so thoroughly trumped cancer’s silent one? To me, the necessary urgency of our coronavirus response stands in stark contrast to the overly aggressive public health messaging used for cancer screening.

The tools used to fight the coronavirus epidemic have been forceful. We’re all diligently washing our hands and staying inside. We’re making sacrifices in our jobs and personal lives to stop the virus’ spread.

Cancer screening has similarly been touted as dogma – an urgent public health intervention that only a fool would turn down. The American Cancer Society once ran an infamous advertisement suggesting that if you decline mammography, you “need more than your breasts examined.” Even today, well-intentioned organizations run cancer screening drives pushing people to pledge to “get screened now.” It is no surprise, then, that I have had patients and family members confide in me that they feel guilty about not pursuing all of their recommended screening tests. The thought of anyone feeling like they caused their own cancer appalls me.

This pressure extends into the clinic. In many practices, primary care doctors are evaluated based on how many patients “comply” with screening recommendations. There seems to be a relentless drive to reach 100% screening penetration. These oversimplified tactics run counter to the shared decision making and informed consent we profess to value in medicine.

The tricky thing about cancer screening is that because most people will never develop the cancer being screened for, we know that most people can also never be helped by it. This doesn’t make screening useless, just as washing your hands can help even if it doesn’t guarantee that you won’t catch coronavirus. We know that some individuals benefit, which we detect at the population level. Overdiagnosis arises in the same way, as a phenomenon detected within populations and not individuals. These aspects of screening are what has led to cancer being viewed as a “societal disease” requiring a uniform response – 100% screening compliance.